New, Groundbreaking Revelation Brings Us Closer to Nuclear Fusion

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Researchers
from the U.S. DOE’s Princeton Plasma Physics Laboratory (PPPL) and Princeton
University may have solved the mystery surrounding magnetic reconnection,
bringing us one step closer to better solar flare prediction and (pmost
notably) problems surrounding nuclear
fusion containment. Ultimately, this means that nuclear fusion, and
the limitless energy it could provide, may be one step closer to reality.

But
to step back for a moment, magnetic reconnection is a process that occurs when
magnetic field lines embedded in plasma come together, break apart, and
explosively reconnect. This occurs in thin plasma sheets where electric energy
is concentrated.

ChamouJacoN/Wikimedia

The
whole process is described by the Sweet-Parker model. But the theory fails to
explain why magnetic reconnection seems to be moving faster than what is
predicted.

The new research details a way to explain the
occurrence of fast reconnection, using a phenomenon called plasmoid
instability. It’s what happens when the plasma sheets start breaking into
plasma “islands.” The researchers were able to come up with a general theory of
the plasmoid instability, and they say that plasmoid instability starts with
a linear phase that follows Sweet-Parker, which then accelerates into an
explosive phase that speeds up reconnection.

They calculated how long each of these phases occurs
and the physics behind each one. In the end, they learned that the process
doesn’t follow power laws, which means that decreasing instability isn’t going
to impact reconnection speed in a predictable way.

Fusion Connection

The
discovery is significant if you consider that magnetic reconnection powers
solar flares, the northern lights, gamma-ray bursts, and other violent natural
phenomena. Calculating just when reconnection speeds up in the Sun means we can
predict solar flares, solar storms, and other freak space weather.

But
it also has an effect on how we look at nuclear fusion. One of the most
prominent ways of generating nuclear fusion is using tokamak fusion reactors.
These trap plasma in magnetic fields in specific areas to force hydrogen to
fuse. In experiments, magnetic reconnection can break these fields. This weakens the hold on the
plasma, meaning it can reach areas in the containment field that won’t allow fusion
to sustain itself. This discovery means we can find ways to strengthen these
magnetic barriers, making for better fusion experiments.